00:02
Okay, in this problem, we have this function, and it kind of looks like this.
00:05
I mean, i'm just going to sketch it.
00:07
It's going up and it's going down, right? something like this.
00:09
So whenever it's increasing, that means as we read it from left to right, our graph is going up.
00:14
So look, from this interval to this interval, it's going from left to right, and it's going up, right? and then similarly, if it's going to the right and our graph is going down, then it's decreasing.
00:24
So from this point to this point, it's going down, right? so that's how we're going to read it.
00:29
Right.
00:29
And then if we're wanting to write it in interval notation, then we would give that interval saying, let's just say that maybe this is negative 5 and this is negative 3.
00:39
Then it would be increasing from, we would say actually probably from a bracket, negative 5.
00:46
Excuse me, to negative 3.
00:48
All right.
00:48
Actually, and we would say it like that.
00:51
Okay, so that's how we're going to say that it's increasing or decreasing in how to write that as an interval.
00:56
Let's look at our picture.
00:58
So it's looking like where is it increasing let's talk about where it's decreasing right so it's coming from negative infinity right and it's decreasing all the way here to negative one so that's how we're going to write it for decreasing right we're going to say i'm just going to say d -ec is decreasing from negative infinity all the way up to negative one right and then it's also decreasing from it looks like one to two right it's decreasing from one to two one to two right, because if we look at it, it's one to two.
01:32
Okay? now increasing, it looks like it's increasing between negative one and positive one.
01:38
So we would say, okay, it's increasing from negative one to positive one.
01:43
And it's also increasing from two up to infinity.
01:46
It keeps going up, right? so from two up to infinity.
01:51
Right...
